Difference between desire (chanda) and craving (tanha)?

What's the difference between desire (chanda) and craving (tanha)? From my understanding, tanha is always unwholesome but chanda can be wholesome or unwholesome. How is this the case? Craving (tanha) arises from feeling as many suttas say "from feeling as a requisite condition comes craving". What does desire (chanda) arise from? There are three types of craving (tanha) - sensual, becoming and unbecoming. How many types of desire (chanda) are there?